The present invention relates to a device for the disruption of explosive ordinance.
Bombs, mines and explosive employed by terrorists and criminals are most commonly improvised explosive devices (IEDs) rather than the conventional munitions (CMs) manufactured for military use. They differ from such military devices in that, with the exception of such small devices as may be made from steel pipe and end-caps, they are most commonly made using containers which are relatively less robust and manufactured for other everyday purposes. These include paper and plastic bags, briefcases, dustbins and beer kegs. Particular problems are encountered when such IEDs are very large and their construction cannot be ascertained. An example is a large vehicle which is laden with explosive material and which may be provided with more than one means of initiation.
The walls of such containers are much more easily penetrated than are those of conventional munitions and a commonly employed method of rendering them safe consists of projecting a mass of water at them. The intention of the method is penetration of the container and tearing it apart or pressurising it to the extent that it bursts, thereby separating the components so quickly that the initiation system does not have time to function. The most common means of thus disrupting IEDs is a heavy steel gun barrel which employs a blank cartridge to discharge a mass of water. This has sufficient velocity to penetrate the wall of many IEDs but is much less likely to cause the explosion or deflagration of their contents than ore projectiles of other materials such as metal. The very high thermal capacity of water limits the temperature rise of the projectile material much more than that imparted to metal projectiles. Since the increments of water originating from the muzzle end of the gun attain a lower velocity than those increments originating from the breach end and accelerated along the entire length of the barrel, the projectile consists of a slug of water with a velocity gradient along the length with the rearmost components travelling fastest. This inherent instability causes the slug of water, once inside its IED target, to scatter violently sideways and to disrupt the target contents.
The effectiveness of such a water jet is mitigated by inherent limitations of velocity obtainable by means of such gun barrels as well as by the instability of the projectile. Muzzle velocities can be increased by the use of heavier and faster burning propellant charges, by longer barrels and by choking the barrel, but such increase is subject to the law of diminishing returns.
A further limitation of disruptors based upon the gun barrel principle is the recoil generated. This exceeds the holding ability of many remote-controlled vehicles used for the deployment of such disruptors. If such a disruptor is fired with inadequate restraint the gun then constitutes a potentially dangerous projectile capable of inflicting greater damage than many small or badly constructed IEDs.
One of my earlier inventions, described in British Patent Specification GB2292445, consists of a disruptor which combines the advantages of high explosive as a propellant with water as a projectile. Unlike conventional deflagrating propellents, high explosive does not need a heavy container to generate extremely high propulsive pressures and imparts directionality to the aqueous projectile by a different mechanism. According to this invention the device is in the form of a shaped charge and water, or some other liquid or liquescent substance, is used to line or to fill the cavity. Like convention meal-lined shaped charges, this device may be used in radially symmetrical forms or in linear forms.
In its radially symmetrical form in particular the velocity of the jet of water enabled it to penetrate the steel or iron body of a mortar bomb and, by suddenly increasing the pressure of the contents, to eject the fuse and booster without explosive reaction.
In its linear embodiment and elongate explosive charge is provided with a cavity which is filled with water.
Since such charges are most conveniently designed using light plastics containers, the assembly disintegrates upon firing and no effective recoil is applied to the means of support. They may therefore be deployed by the smallest of remote-controlled vehicles.
Yet another invention generates a powerful linear jet of water by the simultaneous initiation of two elongate and parallel charges of high explosive each of which is placed along the long axis of a cylindrical container of water. Each charge increment generates a rapidly expanding cylinder of water and, as these two expanding masses collide, a flat elongate jet of water is generated and projected towards the target. A disadvantage of this apparatus is that a similar and equally energetic jet of water is projected in the rearward direction. Since disruptors of this type were intended for the disruption of large vehicle bombs, they are necessarily very large and cumbrous and use tens of kilogrammes of high explosive. One means of deployment of such a large disruptor is a remote controlled vehicle of great expense which is destroyed as the disruptor functions. Further expense may be caused by the rearwardly directed jet and the shock wave produced by the device. This expense is perceived as especially regrettable of the target is subsequently recognized as having not been a functional IED in the first place.
In the case of each of the above inventions a disruptor of a given size will, at a given distance from a target, strike a given area of that target. Since it may be considered necessary or desirable for the effective disruption of that target to strike a larger area of that target, it is necessary in each case either to use a multiplicity of disruptors, all initiated simultaneously, or to use a larger disruptor. The use of a multiplicity of disruptors increases the amount of explosive and the overall charge weight in proportion to the area of the target attacked but it complicates deployment and the means of initiation. Simple increase in the size of a single disruptor in order to strike a larger surface area maintains the simplicity of the arrangement but increases disproportionately the amount of explosive and the overall weight of the charge, and increases the penetrating power to an extent that may be undesirable. Doubling the width of the target which is directly attacked, for example, also doubles the height of the target which is attacked and increases the weight of both of the explosive and overall weight eight-fold.
The present invention provides a device for generating a liquid jet, the device comprising an enclosure containing a plurality of formers, each defining a cavity partially enclosed by the former, each of the formers supporting an explosive charge, and a filler material within the cavity, the filler material being a liquid, a gel or a non-metallic solid that will liquefy upon detonation of the device.
The present invention also provides a device for generating a liquid jet, the device comprising an enclosure containing a former with a plurality of cavities each partially enclosed and supporting an explosive charge, and a filler material with each cavity, the filler material being a liquid, a gel, or a non-metallic solid that will liquefy upon detonation of the device.
The present invention also provides a device for generating a liquid jet, the device comprising an enclosure containing at least one former defining a cavity partially enclosed by the former supporting an explosive charge and a filler material within the cavity, wherein the filler material is a decontaminant.
In this way, according to one aspect of the present invention, there is provided a disruptor with multiple explosive charges in a single outer envelope.
Such a disruptor can provide a well-defined, directed explosive charge, for example which can reproduce accurately the actual or anticipated profile of the target.
Additionally or alternatively, a number of the devices of the present invention can be placed together in a modular form to provide a large-area, uniform explosive charge.
In either form, such a charge can be light-weight and can be assembled quickly and easily.
An object of the present invention is to provide a practicable and convenient means of perforating the case of a large improvised explosive device, such as an explosiveladen road vehicle, using high explosive as the propellent and water as the projected material; another object of the invention is to disrupt and disperse the contents of the target munition so rapidly that its initiation system is unable to function.
A particular application of the invention is the rendering safe of and IED consisting of a large vehicles laden with explosive or containing one or more bombs. It is unlikely that the extent of the explosive fill and the position and nature of the initiation system will be known at the time that the device is recognised as bomb or that a decision is taken to treat it as such. Though it may be assumed that certain parts of the vehicle are more likely to contain explosive than others, it is unlikely that the precise position of the initiation system can be ascertained with certainty even if preliminary entry is made by manual or remote means for the purpose of inspection. The presumption must be made that the perceived initiation system may, in fact, not be the real initiation system or that it is duplicated elsewhere. It may therefore be decided that the safest way to proceed in the disruption of the target is to attack that part of the vehicle which is perceived or suspected of containing an IED or explosive material over sufficient area and with sufficient violence to blow it out of the vehicle and disperse it before the initiation system has time to initiate it or, at least, a significant part of it.
In a preferred embodiment, the shape of the outer container used in the present invention is that of a flat cuboid. This makes it simple and practicable to arrange tow or more disruptors so as to extend the area and shape of the target surface attacked. A parallel array of explosive backed semi-cylindrical formers is arranged against one large inner surface of the outer container with their longitudinal edges adjacent or closely spaced. The explosive charge is applied to either or both surfaces of each former and the space inside the semi-cylinders is filled with water. The area of the target surface which is struck by the projectile water thus depends upon the length of the formers and the overall width of the array. This arrangement provides a means of striking the area attacked with an approximately evenly distributed amount of energy while providing a charge weight which is proportional to the area.
In one simple embodiment of the invention the explosive charge and its formers are placed within an outer container which is itself filled with water. This arrangement suffers the inconvenience of requiring a robustly water-tight outer container.
In another embodiment of the invention the necessity of using a container with a sealed lid capable of containing water without leaking is avoided by employing a rigid outer container and placing a flexible plastics or rubber bladder in the D-sectioned space defined by the inside of each semi-cylindrical former and the flat surface upon which its longitudinal edges abut. These bladders are then filled with water.
The energy imparted to the jet generated by a water-lined or water-filled shaped charge may be enhanced by tamping the explosive, thereby prolonging the duration of the pressure applied to the projected water. A simple means of providing such tamping consists of applying a second body of water to the rear and sides of the explosive charge. This water may also advantageously be contained within one or more flexible bladders occupying the space between the inner wall of the outer case and the convex surface of the cylindrical explosive charges. Such an arrangement has the additional advantage of quenching the hot gases generated by the detonating explosive and eliminating the flash, thereby diminishing considerably the incendive nature of the device. This is particularly desirable when disrupting bombs within, or in the vicinity of, motor vehicles or other highly inflammable structures.
It will be understood that the water may be placed in a single bladder and the explosive charges and their formers placed either within a fold of this liner or within this inflatable bladder. The latter arrangement brings the inconvenience of requiring a large sealable aperture for the insertion of these components.